Analysis Of Vertical Bearing Capacity Of Concrete-Filled Double Skin Steel Tube Columns

Concrete-filled double skin steel tube columns, which have more bending rigidity and fire resistance,but have less weight, are an amelioration of traditional concrete-filled steel tube colums. However, the study of the concrete-filled double skin steel tube columns is at incipient stage. Research report about concrete-filled double skin steel tube columns are very few, and most are about short column constructional element. We could not found the research report about the long column constructional element of Concrete-filled double skin steel tube columns.The mechanics performance under axle compression is experimentally studied, with 3 short column construction elements of cencrete filled double skin steel tube columns and 3 long column construction elements with the same section dimension to short column. Farther, experimetal simulation has been done by finite element method (FEM).Based on the analysis of the test result under axle compression, the stress of core-concrete is three dimensional. Due to the constraint from bilateral steel tube, the mechanics property of core-concrete is advanced. And owing to the exist of core-concrete the inward local buckling of steel tube is resisting, thereby the performance of steel counld be fill exert.The destruction of short column construction elements of cencrete filled double skin steel tube columns is due to local buckling after steel tube into plastic stage. While the construction elements loss the bearing capacity, seval hoop corrugation appear in the steel tube. The destruction of long column construction elements of cencrete filled double skin steel tube columns is destabilization destroy which shape is half-sinusoid. Half-circle corrugation appear about middle and both-end location. The performance of concrete material have not exploited the particular capability.The results of FEM analysis approve the conclusion from experiments. The nonlinear FEM analysis is introduced for theoretical study of the variation of stress and strain with axile compression load in short column construction elements of the cencrete filled double skin steel tube columns and long columns.